A man who robbed a Norwich newsagent at knifepoint has been jailed for seven years after he was described by a judge as posing a 'high risk of serious harm to the public'.

Louis Berks, 41, of Waterloo Road, Norwich, stole £500 from Steve McDonald news in Heartsease, after threatening a member of staff with a knife. She was uninjured but shaken.

Berks, who had previously pleaded guilty to robbery, appeared at Norwich Crown Court yesterday where he was sentenced to seven years with an extended licence period of four years.

Judge Stephen Holt said: 'This was a planned robbery and further this was a vulnerable victim – a female by herself in a shop.'

Judge Holt – who agreed with a probation assessment of Berks stating he was a 'high risk of serious harm to the public' – said he probably had no idea what distress or impact producing a knife caused for vulnerable victims.

He added: 'The profits in these shops are very small and shops all around the country, even in cities, in my opinion, are vulnerable and very vulnerable to this sort of attack.'

Berks shouted 'disgusting' as he was led away before what sounded like a scuffle with the prison guard ensued. Berks' father, who was in the public gallery, also had to be warned 'he would join' his son if his behaviour continued and was asked to leave court.

The owners of the Witard Road shop, Akintola and Abosede Dasaolu, who are parents of Great Britain 2012 Olympic 100m sprinter James Dasaolu, have welcomed the sentence.

Mrs Dasaolu, who was in the back office at the time of the robbery and who has previously spoken of her shock at the incident, said: 'That's great - at least justice has been done.'

Mrs Dasaolu said sentences like this might make people think twice about carrying out these sort of offences.

Earlier Norwich Crown Court heard that Berks robbed the Witard Road store at about 5.40pm on August 31 last year

Andrew Oliver, prosecuting, said Berks first went into the store at about 4.50pm for a 'recce' and had a good look around and seeing that there was 'a sole female working in the shop at that time'.

Mr Oliver said he later returned and waited while a customer was served before going behind the till and producing the knife in his hand 'at stomach height'.

The court heard Berks grabbed between £500 and £550 from the till, none of which was recovered.

Mr Oliver said the victim was left 'shaken and distressed' by the incident.

Jonathan Goodman, mitigating, said Berks, who has 31 convictions for 114 offences dating back to 1987, had a drug addiction but was not a man who was routinely involved in serious violence.

Mr Goodman said Berks took a knife with a three-inch blade and although 'got close to her' said 'nothing other than 'open the till''.

He said: 'He doesn't hold it out, put it to her stomach or throat, simply takes it out of his pocket.'

Have you got a crime story? Call crime correspondent Peter Walsh on 01603 772436 or email peter.walsh@archant.co.uk